1686910196861

This number is a prime.

                                                              168 6910196861

The smallest palindromic Cyclops prime that is 'brilliant' when turned upside down. Brilliant numbers are numbers with two prime factors of the same length, e.g., 1989610169891 = 1291159 × 1540949. The sequence begins 1686910196861, 1996190916991, 186116909611681, ... . [Gaydos]